Embryo Cryopreservation


Embryo cryopreservation or embryo freezing, is a technique that plays a significant role in assisted human reproduction since it allows the preservation of embryos by cooling and storing them at very low temperature for a considerable length of time. The frozen embryos can be then thawed and transferred at a future date (frozen embryo transfer).

Over the past decade, great effort has been put towards the improvement of human cells and tissues cryopreservation.

The freezing of human sperm has been available for decades enabling men to bank sperm before radiation, chemotherapy or surgical procedures that would affect their fertility.

The freezing of embryos is suggested:

  • to prevent wastage of spare embryos after IVF
  • when embryo implantation can be temporarily compromised
  • in women with high risk of developing OHSS

While the cryopreservation of sperm is quite simple due to the small size and low water content of sperm, the freezing of embryos is more complicated since the water has to be removed from all cells of the embryos to avoid ice crystal formation and their damage during the freezing process. To avoid the disruption of embryos, a special fluid (cryoprotectant) is added to the embryo culture to prevent the formation of ice crystals and to allow the embryos to tolerate the reduction in temperature.

The thawing of embryos is also very critical and requires the same meticulous attention to detail. Once the embryos are thawed, they are evaluated under the microscope to assess viability and then transferred into the womb.

According to most studies, children born from frozen embryos are healthy and normal with no increase in birth defects or abnormalities.

For more information on The Fertility Clinic protocols, please take a look at our “Protocols and Procedures” in the “Patient Information” section.